Abramowski, A. and Acero, F. and Aharonian, F. and Akhperjanian, A.G. and Anton, G. and Balenderan, S. and Balzer, A. and Barnacka, A. and Becherini, Y. and Becker Tjus, J. and Behera, B. and Bernlöhr, K. and Birsin, E. and Biteau, J. and Bochow, A. and Boisson, C. and Bolmont, J. and Bordas, P. and Brucker, J. and Brun, F. and Brun, P. and Bulik, T. and Carrigan, S. and Casanova, S. and Cerruti, M. and Chadwick, P.M. and Chaves, R.C.G. and Cheesebrough, A. and Colafrancesco, S. and Cologna, G. and Conrad, J. and Couturier, C. and Dalton, M. and Daniel, M.K. and Davids, I.D. and Degrange, B. and Deil, C. and deWilt, P. and Dickinson, H.J. and Djannati-Ataï, A. and Domainko, W. and Drury, L.O'C. and Dubus, G. and Dutson, K. and Dyks, J. and Dyrda, M. and Egberts, K. and Eger, P. and Espigat, P. and Fallon, L. and Farnier, C. and Fegan, S. and Feinstein, F. and Fernandes, M.V. and Fernandez, D. and Fiasson, A. and Fontaine, G. and Förster, A. and Füßling, M. and Gajdus, M. and Gallant, Y.A. and Garrigoux, T. and Gast, H. and Giebels, B. and Glicenstein, J.F. and Glück, B. and Göring, D. and Grondin, M.-H. and Grudzińska, M. and Häffner, S. and Hague, J.D. and Hahn, J. and Hampf, D. and Harris, J. and Hauser, M. and Heinz, S. and Heinzelmann, G. and Henri, G. and Hermann, G. and Hillert, A. and Hinton, J.A. and Hofmann, W. and Hofverberg, P. and Holler, M. and Horns, D. and Jacholkowska, A. and Jahn, C. and Jamrozy, M. and Jung, I. and Kastendieck, M.A. and Katarzyński, K. and Katz, U. and Kaufmann, S. and Khélifi, B. and Klepser, S. and Klochkov, D . and Kluźniak, W. and Kneiske, T. and Kolitzus, D. and Komin, Nu. and Kosack, K. and Kossakowski, R. and Krayzel, F. and Krüger, P.P. and Laffon, H. and Lamanna, G. and Lefaucheur, J. and Lemoine-Goumard, M. and Lenain, J.-P. and Lennarz, D. and Lohse, T. and Lopatin, A. and Lu, C.-C. and Marandon, V. and Marcowith, A. and Masbou, J. and Maurin, G. and Maxted, N. and Mayer, M. and McComb, T.J.L. and Medina, M.C. and Méhault, J. and Menzler, U. and Moderski, R. and Mohamed, M. and Moulin, E. and Naumann, C.L. and Naumann-Godo, M. and de Naurois, M. and Nedbal, D. and Nguyen, N. and Niemiec, J. and Nolan, S.J. and Ohm, S. and de Oña Wilhelmi, E. and Opitz, B. and Ostrowski, M. and Oya, I. and Panter, M. and Parsons, R.D. and Paz Arribas, M. and Pekeur, N.W. and Pelletier, G. and Perez, J. and Petrucci, P.-O. and Peyaud, B. and Pita, S. and Pühlhofer, G. and Punch, M. and Quirrenbach, A. and Raab, S. and Raue, M. and Reimer, A. and Reimer, O. and Renaud, M. and de los Reyes, R. and Rieger, F. and Ripken, J. and Rosier-Lees, S. and Rowell, G. and Rudak, B. and Rulten, C.B. and Sahakian, V. and Sanchez, D.A. and Santangelo, A. and Schlickeiser, R. and Schulz, A. and Schwanke, U. and Schwarzburg, S. and Schwemmer, S. and Sheidaei, F. and Skilton, J.L. and Sol, H. and Spengler, G. and Stawarz, Ł. and Steenkamp, R. and Stegmann, C. and Stinzing, F. and Stycz, K. and Sushch, I. and Szostek, A. and Tavernet, J.-P. and Terrier, R. and Tluczykont, M. and Trichard, C. and Valerius, K. and van Eldik, C. and Vasileiadis, G. and Venter, C. and Viana, A. and Vincent, P. and Völk, H.J. and Volpe, F. and Vorobiov, S. and Vorster, M. and Wagner, S.J. and Ward, M. and White, R. and Wierzcholska, A. and Wouters, D. and Zacharias, M. and Zajczyk, A. and Zdziarski, A.A. and Zech, A. and Zechlin, H.S. and Rob, L. (2013) 'H.E.S.S. discovery of VHE γ-rays from the quasar PKS 1510−089.', Astronomy and astrophysics., 554 . A107.
The quasar PKS 1510−089 (z = 0.361) was observed with the H.E.S.S. array of imaging atmospheric Cherenkov telescopes during high states in the optical and GeV bands, to search for very high energy (VHE, defined as E ≥ 0.1 TeV) emission. VHE γ-rays were detected with a statistical significance of 9.2 standard deviations in 15.8 h of H.E.S.S. data taken during March and April 2009. A VHE integral flux of I(0.15 TeV < E < 1.0 TeV)= (1.0 ± 0.2stat ± 0.2sys) × 10-11 cm-2 s-1 is measured. The best-fit power law to the VHE data has a photon index of Γ = 5.4 ± 0.7stat ± 0.3sys. The GeV and optical light curves show pronounced variability during the period of H.E.S.S. observations. However, there is insufficient evidence to claim statistically significant variability in the VHE data. Because of its relatively high redshift, the VHE flux from PKS 1510−089 should suffer considerable attenuation in the intergalactic space due to the extragalactic background light (EBL). Hence, the measured γ-ray spectrum is used to derive upper limits on the opacity due to EBL, which are found to be comparable with the previously derived limits from relatively-nearby BL Lac objects. Unlike typical VHE-detected blazars where the broadband spectrum is dominated by nonthermal radiation at all wavelengths, the quasar PKS 1510−089 has a bright thermal component in the optical to UV frequency band. Among all VHE detected blazars, PKS 1510−089 has the most luminous broad line region. The detection of VHE emission from this quasar indicates a low level of γ − γ absorption on the internal optical to UV photon field.
|Keywords:||Gamma rays: galaxies, Quasars: individual: PKS 1510-089, Infrared: diffuse background.|
|Full text:||(VoR) Version of Record|
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|Publisher Web site:||http://dx.doi.org/10.1051/0004-6361/201321135|
|Publisher statement:||Reproduced with permission from Astronomy & Astrophysics, © ESO|
|Date accepted:||28 April 2013|
|Date deposited:||15 July 2014|
|Date of first online publication:||June 2013|
|Date first made open access:||No date available|
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